The Anil Ambani-led Reliance Infrastructure (R-Infra) has asked the power ministry to take up the issue of what it calls "unauthorized levy of marketing margin" by Mukesh Ambani's Reliance Industries for the Krishna-Godavari gas.

The power ministry has been requested to take the matter up with the empowered group of ministers (E-GoM), under Finance Minister Pranab Mukherjee, set up by Prime Minister Manmohan Singh on the issue of supply and pricing of Krishna-Godavari gas.

"The levy of marketing margin has neither been approved by the E-GoM nor by any regulatory authority. But Reliance Industries has included a charge of $0.135 per unit as part of the sale price of gas," the company's chief executive Lalit Jalan said in a letter to the power ministry.

State-owned power utility NTPC, too, had asked the power ministry to ascertain whether the marketing margin levied by Reliance Industries on gas from the Krishna Godavari basin was valid.

The marketing margin is being levied on the hydrocarbon fuel being procured from Reliance Industries for R-Infra's 220 MW Samalkot plant in Andhra Pradesh, based on the allocations made by the government at $4.2 per unit.

"Illegitimate charges such as these directly affect the viability of gas based power generation and hence there is an urgent need to immediately put a stop to such charges. State-owned NTPC had also raised a similar objection earlier," said the letter.

The ministerial group, which includes Petroleum Minister Murli Deora, Power Minister Sushilkumar Shinde, Fertilizer Minister M.K. Alagiri and Law Minister M. Veerappa Moily is scheduled to meet here Oct 27.